Control Strategy for Frequency Support Based on Modular Multilevel Matrix Converter with Emulation Inertia

Stabilized active power from an offshore wind farm is transmitted to the grid through a modular multilevel matrix converter (M ³ C), in which the M ³ C neutron module capacitor operates in a constant voltage state. In this paper, a control strategy based on the M ³ C to provide frequency support is proposed, which simulates the inertia by releasing the energy in the sub-module capacitance in the M ³ C. A frequency-voltage model is established through the linear coupling relationship between frequency and sub-module capacitor voltage. When the system frequency fluctuates, the sub-module capacitors in the M ³ C can absorb or release the energy to simulate the inertia to provide frequency support for the system. Finally, the offshore wind power delivery model based on M ³ C with simulation inertia is built in MATLAB/Simulink, and its results are analyzed and evaluated under load variation.